[Kenny12]

ok I've been away from head-fi for several years and i've sold off most of my gear. I've been looking into getting back into it so i decided to checkout the jaycar headphone amp thats been on offer here in Australia for a very agreeable price of $35.

Heres a short worklog in constructing it.


First I needed a case, lucky for me, I blew up this Hilly Tamp a few days ealier, and its the perfect candidate for our jaycar amp.

Surface Prep

Stuffing the Boards

Giant Input Capacitors Check

I decided to use some botique parts left over from my previous audio days, 470uF Cerafines in the power section instead of the 220uF. I also decided to AK mod this one.

Testing, now the easy part is done

I forgot how hard the locking headphone jacks were to install and I follishly bought one. Because the faceplate aluminum was about 1cm thick! I couldn't get any of my cheap bits to make a good enough hole. After 2 hrs with a tapered reamer and a file, I finally had my hole.

Wiring everything up

Notice the giant bolt i'm using the the transformer that will prevent me from putting the top on, I somehow misplaced the orginal one that came with the transformer.

The bolt was stuck to my multimeter case! I gave up after 30min in trying to find it. I finally noticed it after trying to tuck the leads back into the multimeter!

Inital tests on the night - It sounds pretty good with the A700s at this point.

I decided to upgrade a few more parts, a smt stepped attenulator was sourced from ebay, it sounds exellent for the price. Transistors were also replaced and input caps removed, overall these mods refined the sound quite a bit. I get absloutly no ground noise with this!

Only other mods planned for this little thing is some better diodes in the power supply section and some better capacitors.

Ok so maybie this wasn't a $35 dollar amplifier, but even with upgrades it should come to under $200 AUD.

It sounds exellent on low impediance headphones, it makes the a700 sound awsome, I dont know if i've been ruined by my brief encounter with the hd600 + dynahi but theres just something missing when driving the set of hd580s thats on loan to me.

 

[Nick 214]

Nice Project! Great thread, too.

How do you like those Bennic caps? Dayton re-brands them, too.

NK

 

[elliot42]

Nice build log, good to see another Jaycar amp brought into existence

I'm really enjoying mine.

I, too, was surprised at the lack of noise when I first powered it up. It's the only DIY that I can remember that went absolutely to plan, no ground problems, no hum, no noise. Just silence. And even after taking it apart, adding mods, and putting it back together a number of times.

 

[Kenny12]

i think i like no capacitor more than with

 

[Billyk]

Quote:

The bolt was stuck to my multimeter case! I gave up after 30min in trying to find it. I finally noticed it after trying to tuck the leads back into the multimeter!

Oh man I burst out laughing, that is so me!

 

[splaz]

I have one lying around... it's almost done. I've decided to replace the input caps with film ones.

What did you initially have as the input decoupling cap ?

I replaced all the electrolytic with Panasonics, FM and NHG. Purely because the cheap capacitors that jaycar and altronics stock have bad reputations from places like bad caps.

 

[Kenny12]

i orginally used bennic capacitors but i decided to go with no input capacitors.